They look so bright, appear to fall so far and in the scale of the human mind that struggles to comprehend anything beyond 600 metres away they loom large. Something so fast and bright must be massive.

But it’s mostly dust, little flakes, tiny grains like sand.

Like most things in the universe, the scale and size of what we see confounds us.

Above us now the Geminids are falling, even in the middle of London on a hazy, misty winters night they have been visible.

I say that dust is all it is but that probably misses the point.

What you are seeing is debris, the result of an ‘event’. Every time you see a Geminid you are witnessing the end of little piece of Solar System history, a collision that has produced a curiosity that leaves a trail of dust in the path of our planet.

Most meteor showers we witness are the debris trail from passing comets. The Orionids belong to the famous Halley, Perseids to Swift-Tutle. All that material we see albating to form the coma and then extending for thousands of kilometres behind the comet doesn’t vanish into the vacuum of space. There it sits tracing out the orbit of its parent body and along comes Earth crashing through and we see the result streaking though the sky on a dark clear night. Dust vaporising in the atmosphere.

But the Geminids are different. This is not comet debris. It’s been a shower that has always been curious with its bright slow moving meteors. While the Perseids were first recorded in 36AD the Geminids were only noticed in 1862 and the parent comet was a total mystery. The culprit for the debris trail was discovered in 1983 by two UK scientists Simon Green and John Davies using the IRAS or Infra-red Astronomical Satellite. Named 3200 Paethon, this was no comet but an asteroid.

Arecibo radar image of 3200 Paethon Credit: Arecibo/Cornell

But the curiosity doesn’t end there. This is an asteroid that appears to follow a comet like orbit, making it one of a group of asteroids that come closest to the Sun. It crosses the orbits of Mars, Earth, Venus and Mercury and comes as close as 0.140 AU to the Sun at perihelion. This has earned it the nickname of ‘rock comet’.

3200 Phaethon’s Orbit. Credit: Thierry Lombry

The story still has one more twist. 3200 Paethon, classified as an Apollo asteroid is also thought to be a member of the Pallas Family. This group of dark class B asteroids are all thought to have originated from the Dwarf Planet 2Pallas, probably from one or more impact events as ejecta.

So above your head, vaporising into Earth’s atmosphere is the dust from another world, a proto-world, a remnant of the early years of the Solar System.